J Gastric Cancer.  2013 Sep;13(3):149-156.

Preoperative N Staging of Gastric Cancer by Stomach Protocol Computed Tomography

• Kim SH
• Kim JJ
• Lee JS
• Kim SH
• Kim BS
• Maeng YH
• Hyun CL
• Kim MJ
• Jeong IH

Abstract

PURPOSE
Clinical stage of gastric cancer is currently assessed by computed tomography. Accurate clinical staging is important for the tailoring of therapy. This study evaluated the accuracy of clinical N staging using stomach protocol computed tomography.
MATERIALS AND METHODS
Between March 2004 and November 2012, 171 patients with gastric cancer underwent preoperative stomach protocol computed tomography (Jeju National University Hospital; Jeju, Korea). Their demographic and clinical characteristics were reviewed retrospectively. Two radiologists evaluated cN staging using axial and coronal computed tomography images, and cN stage was matched with pathologic results. The diagnostic accuracy of stomach protocol computed tomography for clinical N staging and clinical characteristics associated with diagnostic accuracy were evaluated.
RESULTS
The overall accuracy of stomach protocol computed tomography for cN staging was 63.2%. Computed tomography images of slice thickness 3.0 mm had a sensitivity of 60.0%; a specificity of 89.6%; an accuracy of 78.4%; and a positive predictive value of 78.0% in detecting lymph node metastases. Underestimation of cN stage was associated with larger tumor size (P<0.001), undifferentiated type (P=0.003), diffuse type (P=0.020), more advanced pathologic stage (P<0.001), and larger numbers of harvested and metastatic lymph nodes (P<0.001 each). Tumor differentiation was an independent factor affecting underestimation by computed tomography (P=0.045).
CONCLUSIONS
Computed tomography with a size criterion of 8 mm is highly specific but relatively insensitive in detecting nodal metastases. Physicians should keep in mind that computed tomography may not be an appropriate tool to detect nodal metastases for choosing appropriate treatment.

Keyword

Stomach neoplasms; Neoplasm staging; Technology, radiologic

MeSH Terms

Humans
Lymph Nodes
Neoplasm Metastasis
Neoplasm Staging
Retrospective Studies
Sensitivity and Specificity
Stomach
Stomach Neoplasms
Technology, Radiologic

Figure

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  Fig. 1 Clinical N staging using stomach protocol computed tomography: A 15 mm sized lymph node (arrows) is seen along the left gastric artery (A, B). This was proven metastatic lymph node by pathological examination.

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  Fig. 2 Clinical N staging using stomach protocol computed tomography: Contrast enhanced computed tomography shows a small lymph node along the lesser curvature (arrows in A, B). The size of this lymph node was 8.3 mm in short diameter on axial image. However, it was no evidence of metastasis by pathological examination.

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  Fig. 3 Clinical N staging using stomach protocol computed tomography: Contrast-enhanced computed tomography shows a 5.3 mm sized lymph node in infrapyloric area (arrows in A, B). The computed tomography number of this lymph node was measured about 115 HU on the average. This was revealed metastatic lymph node by pathological examination.

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